Multiple Search Query In Sql??

Alter procedure sp_Grid(@Id int=null,
@Name varchar(50)=null,
@Dept varchar(50)=null,
@sal int=null,
@type varchar(50)=null
)
as
begin
if(@type='Select')
select * from Test
if(@type='Search')

IF(@Name IS NULL)
    IF(@Dept IS NULL)
IF( @sal IS NULL)
 SELECT * from Test 
      ELSE
SELECT * from Test where sal=@sal
    ELSE 
IF(@sal IS NULL)
SELECT * from Test where Dept=@Dept
ELSE 
SELECT * from Test where Dept=@Dept and sal=@sal
ELSE
    IF(@Dept IS NULL)
IF( @sal IS NULL)
 SELECT * from Test where Name=@Name
   ELSE
SELECT * from Test where Name=@Name AND sal=@sal
    ELSE 
    IF( @sal IS NULL)
 SELECT * from Test where Dept=@Dept AND Name=@Name
   ELSE
SELECT * from Test where Dept=@Dept AND Name=@Name AND sal=@sal

end


 if(txtName.Text=="")
            dm.Name = null;
        else dm.Name = txtName.Text;

        if (txtDept.Text == "")
            dm.Dept = null;
        else dm.Dept = txtDept.Text;

        if (txtSal.Text == "")
            dm.Sal = null;
        else dm.Sal = txtSal.Text;